Automatic trim attachment for power boats

ABSTRACT

A boat having a pair of trim tabs pivotally mounted rearwardly of the transom on transverse axes intermediate the leading and trailing edges of the trim tabs. The trim tabs are operable at slow speeds to lift the rear of the boat and become inoperable at high speeds.

O United States Patent [1113,628,486

[72] inventor Charles H. Bennett [56] References Cited 20400 Nine MileRoad, St. Clair Shores, UNITED STATES PATENTS Mich. 48080 [2]] App. No3,114 3,372,663 3/1968 LoBue ll4/66.5 P [22] Filed Jan. 15, 1970 PrimaryExaminer-Andrew H. Farrell [45] Patented Dec. 21, 1971 Attorney-Barnes,Kisselle, Raisch & (Choate [54] AUTOMATIC TRIM ATTACHMENT FOR POWERBOATS 20 Claims, 7 Drawing Figs.

[52] US. Cl ll4/66.5 P [51] Int. Cl 1363b H22 [50] Field of Search114/665 P ABSTRACT: A boat having a pair of trim tabs pivotally mountedrearwardly of the transom on transverse axes intermediate the leadingand trailing edges of the trim tabs. The trim tabs are operable at slowspeeds to lift the rear of the boat and become inoperable at highspeeds,

PATENIED 05:21 an SHEET 1 BF 2 F'IGUZ FIG.4

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ATTORNEYS PATENIEU DECZI an SHEET 2 [1F 2 INVENTQR CHAPZZJ MBK/V/Vfffmay 0 ATTORNEYS AUTOMATIC TRIM ATTACHMENT FOR POWER BOATS This inventionrelates to boating and particularly to power boats.

BACKGROUND OF THE INVENTION In my U.S. Pat. Nos. 3, 062,167 and3,399,643, there are disclosed and claimed trim attachments for powerboats which comprise trim members that are hinged to the stern of theboat about transverse axes and are adjusted about these axes to providevarying degrees of lift. Such an arrangement permits longitudinal andlateral trimming of the boat under varying load in order to obtainoptimum attitude for movement of the boat through the water and resultsin greater speed with less fuel consumption, improves visibility andpermits adjustment so that compensation can be made for varying loadconditions and can be removed in rough water.

It is well known that at slower speeds a good planing hull is often farfrom its optimum or most efficient planing angle. This is particularlytrue of boats with inboard-outboard en gines wherein a heavy engine ispositioned at the stem with the drive unit aft of the transom. Manyboats of this type are almost impossible to operate at intermediatespeeds such as 8 to 20 miles per hour since the bow rises so steeplythat the operator cannot see anything forwardly.

Among the objects of the present invention are to provide a trimattachment that automatically operates to improve the lift of the rearof the boat at intermediate speeds and becomes automatically inoperableas the boat assumes its correct planing angle at high speeds.

SUMMARY OF THE INVENTION A boat having a pair of trim pivotally mountedrearwardly of the transom of transverse axes intermediate the leadingand trailing edge of the trim tabs. The trim tabs are operable at slowspeeds to lift the rear of the boat and become inoperable at highspeeds. The water flow aft from under the hull rises relative to thehorizontal not relative to the boat, thus the greater the squat thegreater the lift of the tabs. Regardless of the passenger load or thelack of it aboard the boat the trim tabs maintain the boats trim angleto a tolerance of approximately 1.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan view of a boatembodying the invention.

FIG. 2 is a fragmentary perspective view of a boat embodying theinvention.

FIG. 3 is a fragmentary side-elevational view on an enlarged scale of aportion of the boat shown in FIG. 1.

FIG. 4 is a fragmentary sectional view on an enlarged scale taken alongthe line 4 -4 in FIG. 3.

FIG. 5 is a fragmentary plan view of a modified form of the invention.

FIG. 6 is a fragmentary sectional view taken along the line 6-6 in FIG.5.

FIG. 7 is a fragmentary view on a reduced scale of a boat embodying theinvention of FIGS. 5 and 6.

DESCRIPTION Referring to FIG. 1, power boat 10 herein shown as includingan inboard-outboard engine and drive unit 11 has trim members 12pivotally mounted rearwardly of the transom 13 on each side of thecenter line, as presently described.

Two pairs of brackets 14 comprising right angle sections are mounted onthe hull 15. As shown, the brackets 14 are supported in a manner thatthe horizontal flange 16 is fixed to the underside of the boat while thevertical flange 17 extends from the outer edge downwardly. The flanges17 of each pair of brackets 14 face one another.

Each trim member 12 is made of generally uniformly thick material suchas sheet metal and comprises a substantially flat central portion 18, aforward portion 19 which has a lesser length than the portion 18 andextends upwardly at a slight angle, and a front upwardly turned edge 20.Each trim member further includes downwardly extending side flanges 21which extend along the flanges 17 of brackets 14.

The flanges 17 have a plurality of longitudinally spaced openings 22 andthe flanges 21 similarly have openings 23 permitting selectivepositioning of the trim member for pivotal movement about transverseaxes on the brackets 14. As specifically shown in FIG. 4, a bolt 24 isprovided to extend through the openings 23, 22 and a locrknut 25 isthreaded on the end of the bolt. A washer 26 is interposed between theflanges 17, 21 to insure free pivotal movement of the trim members. Ineach position of the trim members, the forward edge 20 is spacedrearwardly from the transom 13 of the boat.

In the idle position of the boat, a projection 26 on the end of eachbracket engages the underside of portion 18 limiting the downwardmovement of the rear portion 18 of the trim member.

In the opposite direction the portion 19 engages the flanges 16 to limitthe downward movement of the front portion 19 as shown in FIG. 3.

In operation, as the boat is operating at slow speeds, there is atendency for the water to follow the hull and move upwardly in the arearearwardly of the transom 1.3. This causes the force of the water toengage the portion 20 maintaining the portion 20 in its broken lineposition as shown in FIG. 3 and thereby causing a lift on the rear ofthe boat. As the speed of the boat increases, the amount of waterstriking the portion 19 is reduced so that the trim member can thenassume the position shown in solid lines in FIG. 3.

It has been found that the length of the portion 19 with respect to theportion 18 produces good results when the ratio of the lengths isapproximately 1:2.

In the form of the invention shown in FIGS. 5-7, the trim members 30 aremade of generally uniformly thick material such as polycarbonate plasticand comprise a central portion 31, flanges 32, a forward portion 33, anda downwardly and rearwardly extending portion 34 hinged to the front ofthe portion 33. A screw 35 is adapted to be threaded through the trimtab into engagement with the portion 34 which forms its secondary trimmember thereby adjusting the angle of the secondary trim ember.

The entire trim member 30 is hinged to a bracket 36 fastened to thetransom 37 of the boat and extending downwardly and rearwardly such thatwhen the trim member is in horizontal position, it is in parallel andspaced above the plane of the underside 38 of the boat.

This form of the invention operates in substantially the same manner asthe previously described form except that the secondary trim member 34permits a further adjustment by changing its angularity.

I claim:

1. In a power boat, the combination comprising:

bracket means extending rearwardly from the stern of the boat on eachside of the centerline of the boat,

a pair of trim members,

means for pivotally mounting each said trim member on each side of thecenterline of the boat intermediate its forward and trailing edges forpivotal movement about a transverse axis in such a manner that the rearportion of said trim members normally extends below the front portion,

the front edge of each said trim member being spaced rearwardly from thestern,

whereby at slow speed the water strikes the forward portions of the trimmembers and as the speed of the boat progresses, the trim members tendto assume a more horizontal position,

each said-trim member including a substantially planar portion andlongitudinally extending downwardly extending flanges thereon.

2. The combination set forth in claim 1 including means for limiting theextent to which the rear of each trim member moves downwardly.

3. The combination set forth in claim 1 wherein said means for pivotallymounting each said trim member on said bracket comprises complementarysurfaces on said bracket and said flanges, and

bolt means extending through openings in said complementary surfaces.

4. The combination set forth in claim 3 wherein said brackets and saidtrim members include interengaging surfaces limiting the downwardmovement of the rear portion of the trim member.

5. The combination set forth in claim 3 wherein said brackets and saidtrim members include longitudinally spaced openings for selectivelypivotally mounting said trim members on said brackets.

6. The combination set forth in claim 1 including an upwardly turnedflange on the front transverse edge of each said trim member.

7. The combination set forth in claim 1 including a rearwardly extendingsecondary trim member on the undersurface of said first-mentioned trimtab and extending rearwardly from the front edge thereof.

8. The combination set forth in claim 7 wherein said trim tab is made ofa material whereby said secondary trim member is integral with saidfirst trim member and connected thereto by an integral hinge at theforward end of the trim member, and

means for adjusting the angular relation of the secondary trim tab withrespect to said first trim tab.

9. The combination set forth in claim 1 including means on at least onesaid bracket for limiting the movement of said trim member to agenerally horizontal position.

10. In a power boat, the combination comprising:

bracket means extending rearwardly from the stern of the boat on eachside of the centerline of the boat,

a pair of trim members,

means for pivotally mounting each said trim member on each side of thecenterline of the boat intermediate its forward and trailing edges forpivotal movement about a transverse axis in such a manner that the rearportion of said trim members normally extends below the front portion,

the front edge of said said trim member being spaced rearwardly from thestern,

whereby at slow speed the water strikes the forward portions of the trimmembers and as the speed of the boat progresses, the trim members tendto assume a more horizontal position,

the ratio of the portion of each trim member which is forwardly of thetransverse pivotal axis to the portion of each trim member rearwardly ofsaid transverse pivotal axis being about 1:2.

11. For use in a power boat, the combination comprising:

bracket means adapted to extend rearwardly from the stern of the boat,

a trim member,

means for pivotally mounting said trim tab intermediate its ends forpivotal movement about a transverse axis in such a manner that the rearportion of said trim member normally extends below the front portion,

the front edge of said trim member being adapted to be spaced rearwardlyfrom the stern,

whereby at slow speed the water will strike the forward portion of thetrim member and as the speed of the boat progresses, the trim memberwill tend to assume a more horizontal position,

said trim member including a substantially planar portion andlongitudinally extending downwardly extending flanges thereon.

12. The combination set forth in claim 11 including means for limitingthe extent to which the rear of the trim member moves downwardly.

13. The combination set forth in claim 11 wherein said means forpivotally mounting said trim member on said bracket comprisescomplementary surfaces on said bracket and said flanges, and

bolt means extending through openings in said complementary surfaces.

14. The combination set forth in claim 13 wherein said brackets and saidtrim member include interengaging surfaces limiting the downwardmovement of the rear portion of the trim member.

15. The combination set forth in claim 13 wherein said brackets and saidtrim member include longitudinally spaced openings for selectivelypivotally mounting said trim member on said brackets.

16. The combination set forth in claim 11 including an upwardly turnedflange on the front transverse edge of said trim member.

17. The combination set forth in claim 11 including a rearwardlyextending secondary trim member on the undersurface of saidfirst-mentioned trim member and extending rearwardly from the front edgethereof.

18. The combination set forth in claim 17 wherein said trim member ismade of a material whereby said secondary trim member is integral withsaid first trim member and connected thereto by an integral hinge at theforward end of the trim member,

and means for adjusting the angular relation of the secondary trimmember with respect to said first trim member.

19. The combination set forth in claim 11 including means on saidbracket for limiting the movement of said trim member to a generallyhorizontal position.

20. For use in a power boat, the combination comprising:

bracket means adapted to extend rearwardly from the stern of the boat,

a trim member,

means for pivotally mounting said trim tab intermediate its ends forpivotal movement about a transverse axis in such a manner that the rearportion of said trim member normally extends below the front portion,

the front edge of said trim member being adapted to be spaced rearwardlyfrom the stern,

whereby at slow speed the water will strike the forward portion of thetrim member and as the speed of the boat progresses, the trim memberwill tend to assume a more horizontal position,

the ratio of the portion of each trim member which is forwardly of thetransverse pivotal axis to the portion of each trim member rearwardly ofsaid transverse pivotal axis being about 1:2.

1. In a power boat, the combination comprising: bracket means extendingrearwardly from the stern of the boat on each side of the centerline ofthe boat, a pair of trim members, means for pivotally mounting each saidtrim member on each side of the centerline of the boat intermediate itsforward and trailing edges for pivotal movement about a transverse axisin such a manner that the rear portion of said trim members normallyextends below the front portion, the front edge of each said trim memberbeing spaced rearwardly from the stern, whereby at slow speed the waterstrikes the forward portions of the trim members and as the speed of theboat progresses, the trim members tend to assume a more horizontalposition, each said trim member including a substantially planar portionand longitudinally extending downwardly extending flanges thereon. 2.The combination set forth in claim 1 including means for limiting theextent to which the rear of each trim member moves downwardly.
 3. Thecombination set forth in claim 1 wherein said means for pivotallymounting each said trim member on said bracket comprises complementarysurfaces on said bracket and said flanges, and bolt means extendingthrough openings in said complementary surfaces.
 4. The combination setforth in claim 3 wherein said brackets and said trim members includeinterengaging surfaces limiting the downward movement of the rearportion of the trim member.
 5. The combination set forth in claim 3wherein said brackets and said trim members include longitudinallyspaced openings for selectively pivotally mounting said trim members onsaid brackets.
 6. The combination set forth in claim 1 including anupwardly turned flange on the front transverse edge of each said trimmember.
 7. The combination set forth in claim 1 including a rearwardlyextending secondary trim member on the undersurface of saidfirst-mentioned trim tab and extending rearwardly from the front edgethereof.
 8. The combination set forth in claim 7 wherein said trim tabis made of a material whereby said secondary trim member is integralwith said first trim member and connected thereto by an integral hingeat the forward end of the trim member, and means for adjusting theangular relation of the secondary trim tab with respect to said firsttrim tab.
 9. The combination set forth in claim 1 including means on atleast one said bracket for limiting the movement of said trim member toa generally horizontal position.
 10. In a power boat, the combinationcomprising: bracket means extending rearwardly from the stern of theboat on each side of the centerline of the boat, a pair of trim members,means for pivotally mounting each said trim member on each side of thecenterline of the boat intermediate its forward and trailing edges forpivotal movement about a transverse axis in such a manner that the rearportion of said trim members normally extends below the front portion,the front edge of said said trim member being spaced rearwardly from thestern, whereby at slow speed the water strikes the forward portions ofthe trim members and as the speed of the boat progresses, the trimmembers tend to assume a more horizontal position, the ratio of theportion of each trim member which is forwardly of the transverse pivotalaxis to the portion of each trim member rearwardly of said transversepivotal axis being about 1:2.
 11. For use in a power boat, thecombination comprising: bracket means adapted to extend rearwardly fromthe stern of the boat, a trim member, means for pivotally mounting saidtrim tab intermediate its ends for pivotal movement about a transverseaxis in such a manner that the rear portion of said trim member normallyextends below the front portion, the front edge of said trim memberbeing adapted to be spaced rearwardly from the stern, whereby at slowspeed the water will strike the forward portion of the trim member andas the speed of the boat progresses, the trim member will tend to assumea more horizontal position, said trim member including a substantiallyplanar portion and longitudinally extending downwardly extending flangesthereon.
 12. The combination set forth in claim 11 including means forlimiting the extent to which the rear of the trim member movesdownwardly.
 13. The combination set forth in claim 11 wherein said meansfor pivotally mounting said trim member on said bracket comprisescomplementary surfaces on said bracket and said flanges, and bolt meansextending through openings in said complementary surfaces.
 14. Thecombination set forth in claim 13 wherein said brackets and said trimmember include interengaging surfaces limiting the downward movement ofthe rear portion of the trim member.
 15. The combination set forth inclaim 13 wherein said brackets and said trIm member includelongitudinally spaced openings for selectively pivotally mounting saidtrim member on said brackets.
 16. The combination set forth in claim 11including an upwardly turned flange on the front transverse edge of saidtrim member.
 17. The combination set forth in claim 11 including arearwardly extending secondary trim member on the undersurface of saidfirst-mentioned trim member and extending rearwardly from the front edgethereof.
 18. The combination set forth in claim 17 wherein said trimmember is made of a material whereby said secondary trim member isintegral with said first trim member and connected thereto by anintegral hinge at the forward end of the trim member, and means foradjusting the angular relation of the secondary trim member with respectto said first trim member.
 19. The combination set forth in claim 11including means on said bracket for limiting the movement of said trimmember to a generally horizontal position.
 20. For use in a power boat,the combination comprising: bracket means adapted to extend rearwardlyfrom the stern of the boat, a trim member, means for pivotally mountingsaid trim tab intermediate its ends for pivotal movement about atransverse axis in such a manner that the rear portion of said trimmember normally extends below the front portion, the front edge of saidtrim member being adapted to be spaced rearwardly from the stern,whereby at slow speed the water will strike the forward portion of thetrim member and as the speed of the boat progresses, the trim memberwill tend to assume a more horizontal position, the ratio of the portionof each trim member which is forwardly of the transverse pivotal axis tothe portion of each trim member rearwardly of said transverse pivotalaxis being about 1:2.